calculate the change in pH when 5 ml of 0.01M HNO3 is added to 50 ml of water.
I know how to calculate pH, but not when it is changing.
HNO3 is a strong acid, so this is fairly straight forward question.
Calculate the new molarity of the acid after being mixed with H2O:
0.01M*0.005L= moles of HNO3.
moles of HNO3/(0.005L+0.05L)= Molarity of HNO3 after addition of water.
Since this is a strong acid, you can just use the following equation:
pH=-log[H^+]
where
[H^+]=Molarity of HNO3 after addition of water.
****Note: Volumes are not additive, but you should get the correct result-- I believe.
Devron is right; volumes are not additive but at these concentrations the difference is strictly theoretical. I don't think you would ever be able to measure it.
Thank you, I was totally over thinking the problem
To calculate the change in pH when an acid is added to water, you need to use the concept of dilution and the initial pH of the water. Here's how you can do it:
1. Find the initial concentration of H+ ions in the water. Since water is neutral, its pH is 7. This corresponds to a concentration of 10^-7 M for H+ ions.
2. Calculate the moles of HNO3 added. To do this, multiply the volume (in liters) of the added acid (5 mL in this case) by its concentration (0.01 M). Remember to convert milliliters to liters by dividing by 1000.
Moles of HNO3 = (5 mL / 1000 mL/L) * 0.01 M
3. Determine the final volume of the solution. Since 5 mL of acid was added to 50 mL of water, the total volume after mixing is 55 mL (since 50 mL + 5 mL = 55 mL).
4. Calculate the final concentration of H+ ions. To do this, divide the moles of HNO3 by the final volume of the solution in liters.
Final concentration of H+ ions = Moles of HNO3 / Final volume (in L)
5. Calculate the new pH using the concentration of H+ ions. The pH of an acidic solution can be found using the formula:
pH = -log[H+]
Take the negative logarithm (base 10) of the concentration of H+ ions to find the new pH.
New pH = -log(final concentration of H+ ions)
6. Finally, find the change in pH by subtracting the initial pH of water (which is 7) from the new pH you calculated.
To summarize, follow these steps:
1. Find the initial concentration of H+ ions in water.
2. Calculate moles of HNO3 added.
3. Determine the final volume of the solution.
4. Calculate the final concentration of H+ ions.
5. Calculate the new pH using the concentration of H+ ions.
6. Find the change in pH by subtracting the initial pH from the new pH.
By following these steps, you should be able to calculate the change in pH when adding 5 ml of 0.01M HNO3 to 50 ml of water.